1. Field of the Invention
The present application relates to a recording medium.
2. Description of the Related Art
A recording medium including an ink receiving layer on a substrate has been known as a recording medium used for recording with ink. The recording medium of this type is being required to have higher ink absorbency as the recording speed is increased.
Japanese Patent Laid-Open No. 2004-1528 discloses a recording medium including two ink receiving layers on a substrate. This recording medium is produced in such a manner that the ratio of the binder content to the pigment content in the ink receiving layer more distant from the substrate can be lower than that in the other ink receiving layer (closer to the substrate). The recording medium thus achieves a high ink absorbency, and in which the adhesion between the substrate and the ink receiving layers is increased to prevent the ink receiving layers from cracking.
Nowadays, there are many cases of binding an on-demand photographic collection containing photographs or combinations of letters and photographs, that is, a photo books or a photo albums in which images are arranged on both sides of each page. In such a binding process, the following method is used in some cases. In the method, images are formed only on one side of a recording medium, and a fold line is formed in the recording medium. A plurality of recording media thus prepared are folded in half along the fold line. Each set of two folded recording media is bonded together with the rear sides facing each other, and the sets of folded recording media are bound together. This binding method allows two pages opposite each other to spread around the fold line, and also allows a large photograph or image to be arranged across two pages, thus providing more high-quality photo books and photo albums than ordinary binding processes. When such a two-page spreadable photo book or photo album is bound, the ink receiving layer of the recording medium is likely to be cracked at the fold line or to peel off partially, thereby degrading the appearance of the image. Accordingly, a recording medium having high resistance to fold cracking (hereinafter referred to as fold crack resistance) is desirable. In addition, it is important that users can turn pages of the photo book smoothly by hand without a sense of discomfort. That is, it is important for the recording to be easy to turn by hand (this characteristic hereinafter referred to as ease of page turning). According to some studies of the present inventors, however, the recording medium disclosed in the above-cited patent document does not have sufficient fold crack resistance or ease of page turning.